Python code coverage for Lib/codeop.py

#	count	content
1	n/a	r"""Utilities to compile possibly incomplete Python source code.
2	n/a
3	n/a	This module provides two interfaces, broadly similar to the builtin
4	n/a	function compile(), which take program text, a filename and a 'mode'
5	n/a	and:
6	n/a
7	n/a	- Return code object if the command is complete and valid
8	n/a	- Return None if the command is incomplete
9	n/a	- Raise SyntaxError, ValueError or OverflowError if the command is a
10	n/a	syntax error (OverflowError and ValueError can be produced by
11	n/a	malformed literals).
12	n/a
13	n/a	Approach:
14	n/a
15	n/a	First, check if the source consists entirely of blank lines and
16	n/a	comments; if so, replace it with 'pass', because the built-in
17	n/a	parser doesn't always do the right thing for these.
18	n/a
19	n/a	Compile three times: as is, with \n, and with \n\n appended. If it
20	n/a	compiles as is, it's complete. If it compiles with one \n appended,
21	n/a	we expect more. If it doesn't compile either way, we compare the
22	n/a	error we get when compiling with \n or \n\n appended. If the errors
23	n/a	are the same, the code is broken. But if the errors are different, we
24	n/a	expect more. Not intuitive; not even guaranteed to hold in future
25	n/a	releases; but this matches the compiler's behavior from Python 1.4
26	n/a	through 2.2, at least.
27	n/a
28	n/a	Caveat:
29	n/a
30	n/a	It is possible (but not likely) that the parser stops parsing with a
31	n/a	successful outcome before reaching the end of the source; in this
32	n/a	case, trailing symbols may be ignored instead of causing an error.
33	n/a	For example, a backslash followed by two newlines may be followed by
34	n/a	arbitrary garbage. This will be fixed once the API for the parser is
35	n/a	better.
36	n/a
37	n/a	The two interfaces are:
38	n/a
39	n/a	compile_command(source, filename, symbol):
40	n/a
41	n/a	Compiles a single command in the manner described above.
42	n/a
43	n/a	CommandCompiler():
44	n/a
45	n/a	Instances of this class have __call__ methods identical in
46	n/a	signature to compile_command; the difference is that if the
47	n/a	instance compiles program text containing a __future__ statement,
48	n/a	the instance 'remembers' and compiles all subsequent program texts
49	n/a	with the statement in force.
50	n/a
51	n/a	The module also provides another class:
52	n/a
53	n/a	Compile():
54	n/a
55	n/a	Instances of this class act like the built-in function compile,
56	n/a	but with 'memory' in the sense described above.
57	n/a	"""
58	n/a
59	n/a	import __future__
60	n/a
61	n/a	_features = [getattr(__future__, fname)
62	n/a	for fname in __future__.all_feature_names]
63	n/a
64	n/a	__all__ = ["compile_command", "Compile", "CommandCompiler"]
65	n/a
66	n/a	PyCF_DONT_IMPLY_DEDENT = 0x200 # Matches pythonrun.h
67	n/a
68	n/a	def _maybe_compile(compiler, source, filename, symbol):
69	n/a	# Check for source consisting of only blank lines and comments
70	n/a	for line in source.split("\n"):
71	n/a	line = line.strip()
72	n/a	if line and line[0] != '#':
73	n/a	break # Leave it alone
74	n/a	else:
75	n/a	if symbol != "eval":
76	n/a	source = "pass" # Replace it with a 'pass' statement
77	n/a
78	n/a	err = err1 = err2 = None
79	n/a	code = code1 = code2 = None
80	n/a
81	n/a	try:
82	n/a	code = compiler(source, filename, symbol)
83	n/a	except SyntaxError as err:
84	n/a	pass
85	n/a
86	n/a	try:
87	n/a	code1 = compiler(source + "\n", filename, symbol)
88	n/a	except SyntaxError as e:
89	n/a	err1 = e
90	n/a
91	n/a	try:
92	n/a	code2 = compiler(source + "\n\n", filename, symbol)
93	n/a	except SyntaxError as e:
94	n/a	err2 = e
95	n/a
96	n/a	if code:
97	n/a	return code
98	n/a	if not code1 and repr(err1) == repr(err2):
99	n/a	raise err1
100	n/a
101	n/a	def _compile(source, filename, symbol):
102	n/a	return compile(source, filename, symbol, PyCF_DONT_IMPLY_DEDENT)
103	n/a
104	n/a	def compile_command(source, filename="<input>", symbol="single"):
105	n/a	r"""Compile a command and determine whether it is incomplete.
106	n/a
107	n/a	Arguments:
108	n/a
109	n/a	source -- the source string; may contain \n characters
110	n/a	filename -- optional filename from which source was read; default
111	n/a	"<input>"
112	n/a	symbol -- optional grammar start symbol; "single" (default) or "eval"
113	n/a
114	n/a	Return value / exceptions raised:
115	n/a
116	n/a	- Return a code object if the command is complete and valid
117	n/a	- Return None if the command is incomplete
118	n/a	- Raise SyntaxError, ValueError or OverflowError if the command is a
119	n/a	syntax error (OverflowError and ValueError can be produced by
120	n/a	malformed literals).
121	n/a	"""
122	n/a	return _maybe_compile(_compile, source, filename, symbol)
123	n/a
124	n/a	class Compile:
125	n/a	"""Instances of this class behave much like the built-in compile
126	n/a	function, but if one is used to compile text containing a future
127	n/a	statement, it "remembers" and compiles all subsequent program texts
128	n/a	with the statement in force."""
129	n/a	def __init__(self):
130	n/a	self.flags = PyCF_DONT_IMPLY_DEDENT
131	n/a
132	n/a	def __call__(self, source, filename, symbol):
133	n/a	codeob = compile(source, filename, symbol, self.flags, 1)
134	n/a	for feature in _features:
135	n/a	if codeob.co_flags & feature.compiler_flag:
136	n/a	self.flags \|= feature.compiler_flag
137	n/a	return codeob
138	n/a
139	n/a	class CommandCompiler:
140	n/a	"""Instances of this class have __call__ methods identical in
141	n/a	signature to compile_command; the difference is that if the
142	n/a	instance compiles program text containing a __future__ statement,
143	n/a	the instance 'remembers' and compiles all subsequent program texts
144	n/a	with the statement in force."""
145	n/a
146	n/a	def __init__(self,):
147	n/a	self.compiler = Compile()
148	n/a
149	n/a	def __call__(self, source, filename="<input>", symbol="single"):
150	n/a	r"""Compile a command and determine whether it is incomplete.
151	n/a
152	n/a	Arguments:
153	n/a
154	n/a	source -- the source string; may contain \n characters
155	n/a	filename -- optional filename from which source was read;
156	n/a	default "<input>"
157	n/a	symbol -- optional grammar start symbol; "single" (default) or
158	n/a	"eval"
159	n/a
160	n/a	Return value / exceptions raised:
161	n/a
162	n/a	- Return a code object if the command is complete and valid
163	n/a	- Return None if the command is incomplete
164	n/a	- Raise SyntaxError, ValueError or OverflowError if the command is a
165	n/a	syntax error (OverflowError and ValueError can be produced by
166	n/a	malformed literals).
167	n/a	"""
168	n/a	return _maybe_compile(self.compiler, source, filename, symbol)